在处理大型的XML文档的时候,在服务器端直接使用XML DOM的时候速度是比较慢的,当我第一次接触到SAX的时候,我意识到我们应该在服务器端将DOM和SAX结合起来以提高我们程序的效率。我们在ASP中最常使用的就是使用COM来完成这个工作(也许你有更好的方法)。
废话少说,还是直接进入实际的代码部分了(下面只是包含了最基本的代码而已)。
首先我们创建一个DLL来封装SAX的功能好了。 测试环境:Win2k Prof.+MSXML3.0 sp1+VB6 要使用SAX我们必须引用(Reference)Microsoft XML 3.0(我的机器安装的是MSXML3.0 sp1)
工程名:SAXTesting
类名:clsSAXTest 方法:Public Function MyXMLParser(XML文件物理路径) as DOMDocument 代码: Option Explicit
Public Function MyXMLParser(ByVal strXMLFilePath As Variant) As DOMDocument Dim reader As New SAXXMLReader Dim contentHandler As New ContentHandlerImpl Dim errorHandler As New ErrorHandlerImpl Set reader.contentHandler = contentHandler Set reader.errorHandler = errorHandler On Error GoTo ErrorHandle Dim XMLFile As String XMLFile = strXMLFilePath reader.parseURL (XMLFile) Dim xmlDoc As MSXML2.DOMDocument Set xmlDoc = CreateObject("MSXML2.DOMDocument") xmlDoc.loadXML strXML Set MyXMLParser = xmlDoc Set xmlDoc = Nothing Exit Function ErrorHandle: Err.Raise 9999, "My XML Parser", Err.Number & " : " & Err.Description
End Function
类名:modPublic 代码: Option Explicit
Global strXML As String
类名:ContentHandlerImpl 代码: Option Explicit
Implements IVBSAXContentHandler
Private Sub IVBSAXContentHandler_startElement(strNamespaceURI As String, strLocalName As String,
strQName As String, ByVal attributes As MSXML2.IVBSAXAttributes) Dim i As Integer intLocker = intLocker + 1 If intLocker > 1 Then End If strXML = strXML & "<" & strLocalName For i = 0 To (attributes.length - 1) strXML = strXML & " " & attributes.getLocalName(i) & "=""" & attributes.getValue(i) &
"""" Next
strXML = strXML & ">" If strLocalName = "qu" Then Err.Raise vbObjectError + 1, "ContentHandler.startElement", "Found element <qu>" End If
End Sub
Private Sub IVBSAXContentHandler_endElement(strNamespaceURI As String, strLocalName As String,
strQName As String) strXML = strXML & "</" & strLocalName & ">" End Sub
Private Sub IVBSAXContentHandler_characters(text As String) text = Replace(text, vbLf, vbCrLf) strXML = strXML & text End Sub
Private Property Set IVBSAXContentHandler_documentLocator(ByVal RHS As MSXML2.IVBSAXLocator)
End Property
Private Sub IVBSAXContentHandler_endDocument()
End Sub
Private Sub IVBSAXContentHandler_endPrefixMapping(strPrefix As String)
End Sub
Private Sub IVBSAXContentHandler_ignorableWhitespace(strChars As String)
End Sub
Private Sub IVBSAXContentHandler_processingInstruction(target As String, data As String) strXML = strXML & "<?" & target & " " & data & ">"
End Sub
Private Sub IVBSAXContentHandler_skippedEntity(strName As String)
End Sub
Private Sub IVBSAXContentHandler_startDocument()
End Sub
Private Sub IVBSAXContentHandler_startPrefixMapping(strPrefix As String, strURI As String)
End Sub
类名:ErrorHandlerImpl 代码: Option Explicit
Implements IVBSAXErrorHandler
Private Sub IVBSAXErrorHandler_fatalError(ByVal lctr As IVBSAXLocator, msg As String, ByVal
errCode As Long) strXML = strXML & "*** error *** " & msg End Sub
Private Sub IVBSAXErrorHandler_error(ByVal lctr As IVBSAXLocator, msg As String, ByVal errCode As
Long) End Sub
Private Sub IVBSAXErrorHandler_ignorableWarning(ByVal oLocator As MSXML2.IVBSAXLocator,
strErrorMessage As String, ByVal nErrorCode As Long)
End Sub
OK,让我们编译这个DLL,应该是没什么问题了。让我们在ASP中看看运行的结果怎么样: XML文件: <?xml version="1.0"?> <root foo="bar.com"> <PARTS> <PART foo="bar.com" foo2="bar.com"> <PARTNO>12345</PARTNO> <DESCRIPTION>VIP - Very Important Part</DESCRIPTION> </PART> <PART> <PARTNO>5678</PARTNO> <DESCRIPTION>LIP - Less Important Part</DESCRIPTION> </PART> </PARTS> </root>
ASP文件: <% Set a = CreateObject("SAXTesting.clsSAXTest") Set xmlDoc = a.MyXMLParser("D:\test.xml") Response.contenttype="text/xml" response.write xmlDoc.xml set xmlDoc=nothing set a=nothing %>
看看结果:-)

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